Navigational problems, specifically determining the position and orientation of objects and controlling and changing the position and orientation of such objects, exist in many areas of personal and commercial endeavor: As one example, off-loading containerized cargo from large ocean-going ships and lighters is hazardous and inefficient during moderate seas, and almost impossible during periods of rough weather and high seas. Conventional cargo handling systems cannot cope with relative motion between ships and lighters under such conditions.
In space exploration, docking spacecraft presents a difficult problem, requiring either a man in the control loop or an extremely sophisticated control system for sensing position of a first space vehicle with which a second space vehicle is to be docked. Present radar and vision-based systems, while adequate to detect distance between two space vehicles to be docked, cannot detect position or orientation of the second vehicle with respect to the first vehicle.
Aircraft landing, especially rotary winged aircraft landing on moving platforms presented by ships, presents a difficult navigational and positioning problem. Currently used radar-based systems are adequate to some degree to detect distance between the helicopter and the landing platform, but provide no information with respect to helicopter orientation vis-a-vis the landing platform. Systems with a person-in-the-loop may detect orientation of the helicopter with respect to the landing platform, but many times fail, especially in bad weather or darkness, to accurately detect distance between the helicopter and the landing platform.
Materials handling similarly presents navigational and positioning problems. Aligning girders during construction of skyscraper framework presents a difficult navigational and positioning problem that is currently solved visually by human operators. The imprecision involved in visual alignment of girders in constructing skyscrapers can lead to an off-specification girder frame, thereby contributing to structural weakness and difficulty in constructing the remainder of the building which is mounted on the girder frame.
Alignment of robotic end effectors or tools with respect to randomly oriented workpieces used in machining and other manufacturing environments also presents a difficult navigational and positioning problem. Current ultrasonic and microwave systems provide some indication of relative distance between a robotic end effector and a workpiece, but present no information with respect to orientation of the effector relative to the workpiece. This has inhibited application of robotic technology in environments less structured than conventional assembly lines.
Remote measurement of ocean waves and earth topological features similarly presents a difficult navigational and positioning problem. Radar and sonar-based systems are only partially effective in measuring distance between a remote sensor and ocean waves or land features. Current radar and sonar-based systems only provide position data when triangulation techniques are used. Triangulation techniques require multiple sending or receiving stations at fixed positions with respect to one another, with high resultant costs.
In computer modeling of time and motion, measurement of three-dimensional objects to provide input data, which is required before computation can be initiated, is a continuing problem. Current techniques measure three-dimensional objects using hand or caliper measurement tools, convert the measured data into machine-readable form and provide such data to a computer. The multiple steps involved make this a cumbersome process.
Visually impaired persons have difficulty walking or otherwise navigating, especially in darkness. Visually impaired and blind persons using canes are limited somewhat in their speed of walking by length of the cane. The longer the cane, the more difficult it is to maneuver. Difficulties encountered in maneuvering the cane detract from the blind or visually impaired person's ability to process information received in a tactile manner from the cane while walking.
There is still a need for an improved system to determine position and orientation of a remote object with respect to a reference coordinate system, especially when one or both of the objects are moving relative to the other. The present invention fills this need.